High-resolution airborne observations of sea-ice pressure ridge sail height

Abstract

Pressure ridges impact the mass, energy and momentum budgets of the sea-ice cover and present an obstacle to transportation through ice-infested waters. Quantifying ridge characteristics is important for understanding total sea-ice mass and for improving the representation of sea-ice dynamics in high-resolution models. Multi-sensor measurements collected during annual Operation IceBridge (OIB) airborne surveys of the Arctic provide new opportunities to assess the sea ice at the end of winter. We present a new methodology to derive ridge sail height from high-resolution OIB Digital Mapping System (DMS) visible imagery. We assess the efficacy of the methodology by mapping the full sail height distribution along 12 pressure ridges in the western and central Arctic. Comparisons against coincident Airborne Topographic Mapper (ATM) elevation anomalies are used to demonstrate the methodology and evaluate DMS-derived sail heights. Sail heights and elevation anomalies were correlated at 0.81 or above. On average mean and maximum sail height agreed with ATM elevation to within 0.11 and 0.49 m, respectively. Of the ridges mapped, mean sail height ranged from 0.99 to 2.16 m, while maximum sail height ranged from 2.1 to 4.8 m. DMS also delivered higher sampling along ridge crests than coincident ATM data.

Mapping Sea Ice Surface Topography in High Fidelity With ICESat‐2

“…ATL03 atmospheric, tidal, and geoid corrections are applied to obtain corrected elevation. Following Duncan et al (2018) and Farrell et al (2015), elevation is the height anomaly relative to the local level ice/water surface.…”

Mosaicking Opportunistically Acquired Very High-Resolution Helicopter-Borne Images over Drifting Sea Ice Using COTS Sensors

“…Additionally, the sea ice drift compensated helicopter-borne images can be used for detailed sea ice deformation studies using the DEM or point cloud extracted from the multi-view images. The small-scale topographic features of sea ice (e.g., pressure ridges) can also be extracted by the shadows cast away from the features in the VHR images (e.g., [ 18 ]).…”

“…VHR images are also useful for assisting fieldwork by recording the detailed sea ice condition or the locations of on-site measurements during the fieldwork period (e.g., [ 14 , 15 ]). Additionally, VHR images can be used independently for figuring out small-scale topographic features of sea ice [ 16 , 17 , 18 ] and extracting pancake ice floe size [ 19 , 20 ] without comparison to satellite remote sensing data.…”

“…Airplanes have been used for image acquisition over a relatively wider area [ 7 ] and enable the employment of multiple sensors (e.g., laser altimeter, radar, and thermal sensor are equipped in the airplane for Operation IceBridge [ 14 , 18 , 21 ]). However, some drawbacks exist, e.g., the higher operational cost and the limited distance of operation, which is restricted by the location of airports or runways, compared to a ship-borne camera, UAV or helicopter carried onboard an icebreaker.…”

Mapping Sea Ice Surface Topography in High Fidelity with ICESat-2

“…ATL03 atmospheric, tidal, and geoid corrections are applied to obtain corrected elevation. Following Duncan et al (2018) and Farrell et al (2015), elevation is the height anomaly relative to the local level ice/water surface.…”